1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_VM_OPTO_OPTOREG_HPP
26 #define SHARE_VM_OPTO_OPTOREG_HPP
27
28 #include "utilities/macros.hpp"
29
30 // AdGlobals contains c2 specific register handling code as specified
31 // in the .ad files.
32 #include CPU_HEADER(adfiles/adGlobals)
33
34 //------------------------------OptoReg----------------------------------------
35 // We eventually need Registers for the Real World. Registers are essentially
36 // non-SSA names. A Register is represented as a number. Non-regular values
37 // (e.g., Control, Memory, I/O) use the Special register. The actual machine
38 // registers (as described in the ADL file for a machine) start at zero.
39 // Stack-slots (spill locations) start at the nest Chunk past the last machine
40 // register.
41 //
42 // Note that stack spill-slots are treated as a very large register set.
43 // They have all the correct properties for a Register: not aliased (unique
44 // named). There is some simple mapping from a stack-slot register number
45 // to the actual location on the stack; this mapping depends on the calling
46 // conventions and is described in the ADL.
47 //
48 // Note that Name is not enum. C++ standard defines that the range of enum
49 // is the range of smallest bit-field that can represent all enumerators
50 // declared in the enum. The result of assigning a value to enum is undefined
51 // if the value is outside the enumeration's valid range. OptoReg::Name is
52 // typedef'ed as int, because it needs to be able to represent spill-slots.
53 //
54 class OptoReg {
55
56 friend class C2Compiler;
57 public:
58 typedef int Name;
59 enum {
60 // Chunk 0
61 Physical = AdlcVMDeps::Physical, // Start of physical regs
62 // A few oddballs at the edge of the world
63 Special = -2, // All special (not allocated) values
64 Bad = -1 // Not a register
65 };
66
67 private:
68
69 static const VMReg opto2vm[REG_COUNT];
70 static Name vm2opto[ConcreteRegisterImpl::number_of_registers];
71
72 public:
73
74 // Stack pointer register
75 static OptoReg::Name c_frame_pointer;
76
77
78
79 // Increment a register number. As in:
80 // "for ( OptoReg::Name i; i=Control; i = add(i,1) ) ..."
81 static Name add( Name x, int y ) { return Name(x+y); }
82
83 // (We would like to have an operator+ for RegName, but it is not
84 // a class, so this would be illegal in C++.)
85
86 static void dump(int, outputStream *st = tty);
87
88 // Get the stack slot number of an OptoReg::Name
89 static unsigned int reg2stack( OptoReg::Name r) {
90 assert( r >= stack0(), " must be");
91 return r - stack0();
92 }
93
94 static void invalidate(Name n) {
95 vm2opto[n] = Bad;
96 }
97
98 // convert a stack slot number into an OptoReg::Name
99 static OptoReg::Name stack2reg( int idx) {
100 return Name(stack0() + idx);
101 }
102
103 static bool is_stack(Name n) {
104 return n >= stack0();
105 }
106
107 static bool is_valid(Name n) {
108 return (n != Bad);
109 }
110
111 static bool is_reg(Name n) {
112 return is_valid(n) && !is_stack(n);
113 }
114
115 static VMReg as_VMReg(OptoReg::Name n) {
116 if (is_reg(n)) {
117 // Must use table, it'd be nice if Bad was indexable...
118 return opto2vm[n];
119 } else {
120 assert(!is_stack(n), "must un warp");
121 return VMRegImpl::Bad();
122 }
123 }
124
125 // Can un-warp a stack slot or convert a register or Bad
126 static VMReg as_VMReg(OptoReg::Name n, int frame_size, int arg_count) {
127 if (is_reg(n)) {
128 // Must use table, it'd be nice if Bad was indexable...
129 return opto2vm[n];
130 } else if (is_stack(n)) {
131 int stack_slot = reg2stack(n);
132 if (stack_slot < arg_count) {
133 return VMRegImpl::stack2reg(stack_slot + frame_size);
134 }
135 return VMRegImpl::stack2reg(stack_slot - arg_count);
136 // return return VMRegImpl::stack2reg(reg2stack(OptoReg::add(n, -arg_count)));
137 } else {
138 return VMRegImpl::Bad();
139 }
140 }
141
142 static OptoReg::Name as_OptoReg(VMReg r) {
143 if (r->is_stack()) {
144 assert(false, "must warp");
145 return stack2reg(r->reg2stack());
146 } else if (r->is_valid()) {
147 // Must use table, it'd be nice if Bad was indexable...
148 return vm2opto[r->value()];
149 } else {
150 return Bad;
151 }
152 }
153
154 static OptoReg::Name stack0() {
155 return VMRegImpl::stack0->value();
156 }
157
158 static const char* regname(OptoReg::Name n) {
159 return as_VMReg(n)->name();
160 }
161
162 };
163
164 //---------------------------OptoRegPair-------------------------------------------
165 // Pairs of 32-bit registers for the allocator.
166 // This is a very similar class to VMRegPair. C2 only interfaces with VMRegPair
167 // via the calling convention code which is shared between the compilers.
168 // Since C2 uses OptoRegs for register allocation it is more efficient to use
169 // VMRegPair internally for nodes that can contain a pair of OptoRegs rather
170 // than use VMRegPair and continually be converting back and forth. So normally
171 // C2 will take in a VMRegPair from the calling convention code and immediately
172 // convert them to an OptoRegPair and stay in the OptoReg world. The only over
173 // conversion between OptoRegs and VMRegs is for debug info and oopMaps. This
174 // is not a high bandwidth spot and so it is not an issue.
175 // Note that onde other consequence of staying in the OptoReg world with OptoRegPairs
176 // is that there are "physical" OptoRegs that are not representable in the VMReg
177 // world, notably flags. [ But by design there is "space" in the VMReg world
178 // for such registers they just may not be concrete ]. So if we were to use VMRegPair
179 // then the VMReg world would have to have a representation for these registers
180 // so that a OptoReg->VMReg->OptoReg would reproduce ther original OptoReg. As it
181 // stands if you convert a flag (condition code) to a VMReg you will get VMRegImpl::Bad
182 // and converting that will return OptoReg::Bad losing the identity of the OptoReg.
183
184 class OptoRegPair {
185 friend class VMStructs;
186 private:
187 short _second;
188 short _first;
189 public:
190 void set_bad ( ) { _second = OptoReg::Bad; _first = OptoReg::Bad; }
191 void set1 ( OptoReg::Name n ) { _second = OptoReg::Bad; _first = n; }
192 void set2 ( OptoReg::Name n ) { _second = n + 1; _first = n; }
193 void set_pair( OptoReg::Name second, OptoReg::Name first ) { _second= second; _first= first; }
194 void set_ptr ( OptoReg::Name ptr ) {
195 #ifdef _LP64
196 _second = ptr+1;
197 #else
198 _second = OptoReg::Bad;
199 #endif
200 _first = ptr;
201 }
202
203 OptoReg::Name second() const { return _second; }
204 OptoReg::Name first() const { return _first; }
205 OptoRegPair(OptoReg::Name second, OptoReg::Name first) { _second = second; _first = first; }
206 OptoRegPair(OptoReg::Name f) { _second = OptoReg::Bad; _first = f; }
207 OptoRegPair() { _second = OptoReg::Bad; _first = OptoReg::Bad; }
208 };
209
210 #endif // SHARE_VM_OPTO_OPTOREG_HPP